1. Field of the Invention
The present invention relates to a lift assembly and, more particularly, to a battery powered lift assembly with a support platform and, most particularly, to a battery powered lift assembly with a support platform that is suitable for use by an individual with limited mobility.
2. Background Information
The present invention pertains to a portable vertical lift, as may be used to lift wheelchair-bound hunters to an elevated location, as well as other uses for the portable vertical lift. As our society progresses, the number of activities which are accessible to the physically disadvantaged, or in which the physically disadvantaged desire to participate, is also increasing. Sports for the wheelchair-bound, such as racing and basketball, are no exceptions to this trend, and hunting is included among these sports. However, in many cases, the physically disadvantaged present unique needs, and special devices are required to allow for their full participation. For example, a physically disadvantaged hunter confined to a wheelchair presents a real challenge. It is common for hunters to construct a tree stand in a tree and then wait in the tree stand for game to come by. Such a feat is extremely impractical for a hunter confined to a wheelchair. A need exists for a technology to overcome this barrier to the disabled hunter.
Various devices have been employed for raising and/or lowering a load along a vertical structure. Some of these devices have been patented, including the following.
Schuchert, in U.S. Pat. No. 2,531,346, discloses a builder's hoist having a mast comprising sections capable of being connected end to end. A support for a cable-carrying pulley is attached at the upper end of the top mast section. Means are provided to hold a lift in an elevated position, independently of a hoist mechanism. An additional section for the mast, therefor, can be lifted to the top of the mast, and on locking of the lift against downward movement, the pulley support is removable from the top of the mast, and attachable to one end of the additional section, after which such section is connected at its opposite end on the mast. In this operation the lift functions as a stationary working platform. An extension of the mast, as required in the erection of a structure, is thus readily accomplished by utilizing the hoist itself for such purposes.
Slais, in U.S. Pat. No. 3,276,546, describes a knock down building material elevator system for mounting to the side of a structure. A carriage holding a platform is raised/lowered along the vertical support by a cable extending from an electric motor at the tip of the vertical support.
In U.S. Pat. No. 3,517,774, Meyer discloses a hoist apparatus comprising a tubular track affixed to a vertical wall and made up of a plurality of reinforced, polygonal-shaped sections. The side walls of the tubular track intersecting in vertical corners within which the wheels of a carriage permanently installed inside of the track are rotatably supported. An elevator car is removably attached to the carriage through a slot extending the length of the tubular tack, and a safety, brake mechanism is mounted on the carriage. The brake mechanism includes spring-loaded brake shoes, which are urged outwardly into frictional engagement with the inside walls of the tubular track in response to the severing of the lift cable for the carriage. The carriage wheels are rotatably supported on pivotal brackets and are biased outwardly against the inside of the tubular track by shock absorbing springs.
Brown, in U.S. Pat. No. 4,353,308, describes a cog wheel vehicle system. A single track consists of a square beam having a pair of flanges. There is a row of holes in each flange (FIG. 3). A vehicle rides on the track and has a cog wheel engaging the holes in the flange. A directional hydraulic motor is connected to drive the cog wheel. A hydraulic pump is connected to drive the motor. A gasoline engine is pivotally mounted on the vehicle and is connected to drive the pump.
In U.S. Pat. No. 4,633,538, James discloses an invalid hoist that includes a base having a column support socket, an upstanding column detachably mounted in the socket and a lifting arm extending from the column. The arm is movable along the column by a screw-and-nut lifting mechanism within the column, with the nut of the mechanism being coupled to the arm. A reversible electric motor unit and battery for energization of the motor are mounted on the base with an output shaft of a reduction gear box of the motor unit aligned with and directly coupled to the lower end of the screw of the lifting mechanism to provide a drive from the motor to the screw, through the socket. The drive between the output shaft and the screw is provided by a coupling, which can readily be broken to enable the column to be detached from the base without disturbing the motor.
Eberle, in U.S. Pat. No. 4,862,997, describes a wheel chair with elevating seat having a high lift capability. The device includes a frame assembly having a plurality of wheels attached to and normally supporting the frame assembly. A pair of opposed, vertical track members is attached to and projects upwardly from the frame assembly, and elements are provided for selectively moving a chair substantially along the lengths of the track members. The lengths of the track members provide high lift capabilities for the chair, while permitting passage through standard residential door openings. Thus, the operator is enabled to perform household and other tasks, which otherwise would not be possible.
In U.S. Pat. No. 4,987,976, Daugherty discloses a manually-operated portable lift which telescopically raises its mast or post so as to raise a lifting platform above the lift's initial height. The lift folds up to a compact and easily-moved configuration for ease of transport and storage. The lift includes a base with built-in outriggers, which easily snap out to fixed extended positions and return to their storage positions. The outrigger is automatically latched in either such position but not between them. The base portion forward of the post manually unlatches and folds up parallel to the post. The platform and its arms have provision for manually mounting the arms of the platform in a low lifting position, a high lifting position, and a compact storage position wherein the arms are adjacent the platform. An extension mast is provided in either a storage position adjacent the main mast or as an extension of that mast. A manual winch is provided with dual handles—one long and one short—for greater or lesser mechanical advantage and slower or faster operation.
Harris, in U.S. Pat. No. 5,070,972, describes a thin flexible track of spring steel having a series of perforations there through for use in conjunction with a variable speed travel carriage, having a carriage drive sprocket which is studded about the periphery with balls or spherical members adapted to mesh with the track perforations to drive the carriage along. By this arrangement, greater loads may be driven than was hitherto possible with known flexible-track devices requiring the use of a guide and drive track following the contour of workpiece upon which work is being carried out.
In U.S. Pat. No. 5,102,179, Royer discloses a hunter's blind having hinged walls, which may be fastened together, when in a vertical position and compactly stored when in a horizontal position. A connecting roof is present and ball rollers cooperate with openings in leg sections to raise and lower the hunter's blind. Stabilizing cables are played out and taken up simultaneously with the raising and lowering of the hunter's blind. Controls located within the hunter's blind enable the user to control the raising and lowering of the hunter's blind and the deployment of the stabilizing cables, while remaining within the blind.
Wooden, in U.S. Pat. No. 5,322,408, describes a device for raising and lowering an impaired person between the ground and a higher level for boarding and deplaning from an airplane. The device comprises a wheeled frame and a hydraulic lift for raising and lowering the person. The hydraulic lift extends upwardly from the wheeled frame. The device also comprises a platform oriented transversely in relation to the hydraulic lift, the platform being adapted for supporting the impaired person or a wheelchair in which the person reposes. The device also has a protective enclosure mounted upon the platform which surrounds the impaired person.
In U.S. Pat. No. 5,595,265, Lebrocquy discloses a portable apparatus for raising and lowering a load vertically along a substantially vertical structure. The apparatus comprises a vertical guide, which is secured to the substantially vertical structure by a retainer. A carriage is movably attached to the vertical guide, and a platform, which supports the load, is attached to the carriage. The carriage is raised and lowered along the vertical guide by some means, whereby the load is raised and lowered along the vertical guide. The carriage also comprises a safety brake for immobilizing the carriage with respect to the vertical guide, when the means for raising and lowering the carriage is inoperative or malfunctions. Note the various structures for attachment to the vertical guide. The apparatus further comprises wheels rotatingly attached to the bottom of the vertical guide and a hitch attached to the top of the vertical guide, such that the entire device may be towed behind a vehicle.
Horcher et al., in U.S. Pat. No. 5,960,909 describe a person lifter, particular a pool lifter, including a rotatable column that begins at a base mount, and with a person holder, such as a seat or gurney, that can be raised or lowered by a lifting arm along the longitudinal axis of the column. In order to stop the person holder in the event of a malfunction, or if the lowering speed of the person holder is excessively high, the lifting arm begins at a first driven belt (conveyor belt) guided in the column, parallel to which a second belt (catch belt) guided in the column and joined to the lifting arm is arrested if the lowering speed of the person holder exceeds a predetermined value.
In U.S. Pat. No. 5,979,602, Grout discloses a hoist that aids in construction and/or maintenance tasks at elevated heights. The hoist is equipped with a centrally located stabilizer, through which a steel cable connected to an electrically operated winch is routed. The hoist is raised and lowered through the use of a control station located within reach of the seat.
Edwards, in U.S. Pat. No. 6,640,934, describes a cargo lift for transporting goods between ground level and a raised handling position at the side of a building. The lift includes a vertical mast extending between ground level and the handling position alongside the building. A cargo container for carrying the goods is attached to a rolling sleeve carried on the mast. An electric winch raises the cargo container along the mast between ground level and raised handling position.
Applicants have devised a battery powered vertical lift assembly suitable for use by any individual, including an individual confined to a wheelchair. The battery powered vertical lift assembly is also suitable for other applications where raising and/or lowering a load vertically is required.